P661: EFFECT OF VITAMIN K2 ON COVID-19 S1 PROTEIN-INDUCED CYTOTOXICITY AGAINST HUVECS AND ON THE ACTION OF ASCIMINIB IN ABELSON-TYROSINE-KINASE-INHIBITOR-RESISTANT CHRONIC MYELOGENOUS LEUKEMIA CELLS
Authors: Seiichi Okabe, Mitsuru Moriyama, Akihiko Gotoh
Journal: HemaSphere (2023)

Background: Abelson (ABL) tyrosine kinase inhibitors (TKIs) are effective against chronic myelogenous leukemia (CML). However, a certain number of patients develop resistance during ABL TKI therapy. Vitamin K2 (VK2) is a crucial fat-soluble vitamin and is used to activate hepatic coagulation factors and treat osteoporosis. Asciminib, also known as ABL001, could transform the standard of care in this population through its novel mechanism of action of specifically targeting the ABL myristoyl pocket (STAMP) inhibitor. Further, the COVID-19 pandemic also raised new concerns for CML patients. Aims: We investigated whether VK2 enhances STAMP inhibitor, asciminib, and affect the COVID-19 response of HUVECs. Methods: In this work, we assessed the anti-CML cell activity of VK2. We examined whether VK2 contributed to the COVID-19 response by using THP-1 derived macrophage. We also investigated the efficacy of VK2 and asciminib by using CML cell lines, K562, ponatinib-resistant K562 (K562 PR), Ba/F3 BCR–ABL, and T315I point mutant Ba/F3 (Ba/F3 T315I) cells. Results: According to a previous study, individuals in CML who do not experience an early molecular response to imatinib will likely have worse outcomes. Based on data from the Gene Expression Omnibus (GEO) database, gamma-glutamyl carboxylase (GGCX) and vitamin K epoxide reductase complex subunit 1 (VKORC1) were elevated in imatinib-resistant patients (GSE130404). UBIA Prenyltransferase Domain Containing 1 (UBIAD1) was decreased suggested that VK2-related genes were involved ABL TKI resistance. The third generation ABL TKI, ponatinib inhibited the proliferation of CML cell lines, including Ba/F3 T315I cells. In contrast, the ponatinib-resistant cell line, K562 PR, is less sensitive to ponatinib. Asciminib inhibited CML cells and ponatinib resistance in a dose-dependent manner. VK2 also inhibited the proliferation of CML cell lines. Cytotoxicity was also increased by VK2 treatment. Caspase 3/7 activity was also elevated, as was cellular cytotoxicity. VK2 plus asciminib therapy induced a significantly higher level of cytotoxicity than use of each drug alone. To determine the anticancer effects of VK2 and asciminib, we next investigated the long-term effects of VK2 and asciminib singly and their combined effects in colony formation assays. We found colony count was reduced by the combination of VK2 and asciminib. Treatment with VK2 and asciminib for 24 hours increased the percentages of K562 and K562 PR cells in the G1 compared with the controls. Compared with control samples, VK2 and asciminib co-treatment decreased the activity of the 20S proteasome. Also, VK2 plus asciminib therapy altered the mitochondrial membrane potential. To investigate the effect of VK2 on cytotoxicity of the COVID-19 S1 protein against human umbilical vein endothelial cells (HUVEC), we used THP-1 cell line which induced macrophage differentiation by phorbol 12-myristate 13-acetate (PMA). Secretion of inflammatory cytokines, such as interleukin 1 beta (IL-1B) was increased by COVID-19 S1 protein in a dose dependent manner. Cell culture supernatant from PMA with COVID-19 S1 protein inhibited cell growth of HUVECs and induced cytotoxicity. We found that VK2 inhibited 20S proteasome activity of THP-1 by PMA treatment. Simultaneously, cytotoxicity of HUVEC from cell culture supernatant of PMA with COVID-19 S1 was reduced by the treatment with VK2. Summary/Conclusion: VK2 and asciminib are suggested as a novel approach for treatment of ABL-TKI-resistant cells since they increase treatment efficacy. Additionally, VK2 may also have a positive effect for CML patients infected with COVID-19. Keywords: COVID-19, Asciminib, Chronic myeloid leukemia